lib: Simplify implementation of uhd::get_system_time() to use <chrono>

uhd::get_system_time() is currently only used in USRP1 code, and it
turns out that our "optimized", platform-dependent implementation still
is a little slower than straight-up chrono. We therefore remove all the
special cases, and replace them with a single, standard solution.

2 files changed, 8 insertions, 108 deletions

diff --git a/host/lib/utils/CMakeLists.txt b/host/lib/utils/CMakeLists.txt
index 5c4478909..4369a8f11 100644
--- a/host/lib/utils/CMakeLists.txt
+++ b/host/lib/utils/CMakeLists.txt
@@ -132,68 +132,6 @@ set_source_files_properties(
 )
 
 ########################################################################
-# Setup defines for high resolution timing
-########################################################################
-message(STATUS "")
-message(STATUS "Configuring high resolution timing...")
-include(CheckCXXSourceCompiles)
-
-set(CMAKE_REQUIRED_LIBRARIES -lrt)
-CHECK_CXX_SOURCE_COMPILES("
-    #include <ctime>
-    int main(){
-        timespec ts;
-        return clock_gettime(CLOCK_MONOTONIC, &ts);
-    }
-    " HAVE_CLOCK_GETTIME
-)
-set(CMAKE_REQUIRED_LIBRARIES)
-
-include(CheckCXXSourceCompiles)
-CHECK_CXX_SOURCE_COMPILES("
-    #include <mach/mach_time.h>
-    int main(){
-        mach_timebase_info_data_t info;
-        mach_timebase_info(&info);
-        mach_absolute_time();
-        return 0;
-    }
-    " HAVE_MACH_ABSOLUTE_TIME
-)
-
-CHECK_CXX_SOURCE_COMPILES("
-    #include <Windows.h>
-    int main(){
-        LARGE_INTEGER value;
-        QueryPerformanceCounter(&value);
-        QueryPerformanceFrequency(&value);
-        return 0;
-    }
-    " HAVE_QUERY_PERFORMANCE_COUNTER
-)
-
-
-if(HAVE_CLOCK_GETTIME)
-    message(STATUS "  High resolution timing supported through clock_gettime.")
-    set(SYSTEM_TIME_DEFS HAVE_CLOCK_GETTIME)
-    LIBUHD_APPEND_LIBS("-lrt")
-elseif(HAVE_MACH_ABSOLUTE_TIME)
-    message(STATUS "  High resolution timing supported through mach_absolute_time.")
-    set(SYSTEM_TIME_DEFS HAVE_MACH_ABSOLUTE_TIME)
-elseif(HAVE_QUERY_PERFORMANCE_COUNTER)
-    message(STATUS "  High resolution timing supported through QueryPerformanceCounter.")
-    set(SYSTEM_TIME_DEFS HAVE_QUERY_PERFORMANCE_COUNTER)
-else()
-    message(STATUS "  High resolution timing supported though microsec_clock.")
-    set(SYSTEM_TIME_DEFS HAVE_MICROSEC_CLOCK)
-endif()
-
-set_source_files_properties(
-    ${CMAKE_CURRENT_SOURCE_DIR}/system_time.cpp
-    PROPERTIES COMPILE_DEFINITIONS "${SYSTEM_TIME_DEFS}"
-)
-
-########################################################################
 # Setup defines for module loading
 ########################################################################
 message(STATUS "")
diff --git a/host/lib/utils/system_time.cpp b/host/lib/utils/system_time.cpp
index 20b6dc429..71fcd3fff 100644
--- a/host/lib/utils/system_time.cpp
+++ b/host/lib/utils/system_time.cpp
@@ -5,50 +5,12 @@
 //
 
 #include <uhdlib/utils/system_time.hpp>
-
-using namespace uhd;
-
-#ifdef HAVE_CLOCK_GETTIME
-#include <time.h>
-time_spec_t uhd::get_system_time(void){
-    timespec ts; clock_gettime(CLOCK_MONOTONIC, &ts);
-    return time_spec_t(ts.tv_sec, ts.tv_nsec, 1e9);
-}
-#endif /* HAVE_CLOCK_GETTIME */
-
-
-#ifdef HAVE_MACH_ABSOLUTE_TIME
-#include <mach/mach_time.h>
-time_spec_t uhd::get_system_time(void){
-    mach_timebase_info_data_t info; mach_timebase_info(&info);
-    intmax_t nanosecs = mach_absolute_time()*info.numer/info.denom;
-    return time_spec_t::from_ticks(nanosecs, 1e9);
-}
-#endif /* HAVE_MACH_ABSOLUTE_TIME */
-
-
-#ifdef HAVE_QUERY_PERFORMANCE_COUNTER
-#include <Windows.h>
-time_spec_t uhd::get_system_time(void){
-    LARGE_INTEGER counts, freq;
-    QueryPerformanceCounter(&counts);
-    QueryPerformanceFrequency(&freq);
-    return time_spec_t::from_ticks(counts.QuadPart, double(freq.QuadPart));
-}
-#endif /* HAVE_QUERY_PERFORMANCE_COUNTER */
-
-
-#ifdef HAVE_MICROSEC_CLOCK
-#include <boost/date_time/posix_time/posix_time.hpp>
-namespace pt = boost::posix_time;
-time_spec_t uhd::get_system_time(void){
-    pt::ptime time_now = pt::microsec_clock::universal_time();
-    pt::time_duration time_dur = time_now - pt::from_time_t(0);
-    return time_spec_t(
-        int64_t(time_dur.total_seconds()),
-        long(time_dur.fractional_seconds()),
-        double(pt::time_duration::ticks_per_second())
-    );
+#include <chrono>
+
+uhd::time_spec_t uhd::get_system_time(void)
+{
+    const auto now = std::chrono::steady_clock::now().time_since_epoch();
+    const auto seconds = std::chrono::duration_cast<std::chrono::seconds>(now);
+    const auto nanoseconds = std::chrono::duration_cast<std::chrono::nanoseconds>(now-seconds);
+    return uhd::time_spec_t(seconds.count(), nanoseconds.count(), 1e9);
 }
-#endif /* HAVE_MICROSEC_CLOCK */
-